Determining pool volume

I have an 18x36 roman end vinyl in-ground with 4x6 steps, which makes it close to 42 in length. It has an 8.5 foot deep end and a 3 foot shallow end. All these years I have been assuming the pool holds about 36,000 gallons. Am I correct? What is the equation for determining volume in both litres & gallons?

Also, the chlorine calculator by Mr Smith at
http://www.hal-pc.org/~mwsmith2/BleachCalc262.exe refers in Litres, not gallons.

LOVE this site (been a convert since 1996 - changed my life - in pool terms that is).

Thanks!

I can't help you with the volume but bleach calc has a settings tab that will let you enter your numbers as gallons or liters. It will also save the numbers for your pool so you won't have to enter them everytime you use the calc.

The forumla for a rectangular pool is:
length (in ft) x width (in ft) x average depth (in ft) x 7.48 (gallons per cubic foot) = volume in gallons.

Using BleachCalc and assuming an average depth of 5.75 feet, I get just under 28000 gallons. The steps probably only add about 300-400 gallons.

You can change Michael's BleachCalc from the metric to the imperial system by selecting "settings" from the "more calcs" menu.

If you want a real accurate number, you'll need to measure it:

measure the depth of water in a line down the center of the pool every 1 foot (ignoring the stairs for now) , you should end up with 37 measurements (0 ft, 1ft, 2ft, .... 35ft, 36ft).

Calculate the "average" depth for each 1 foot long x 18 feet wide section by averaging the depth reading at start and end of that 1 foot section but subtracting maybe 2 or 3 inches for rounding at the sides of the pool. Then multiple this average depth for this section by 18' x 1' to get xxx cubic feet for this 1 ft long section

Do this for all 36 sections, add up all 36 values of cubic feet, multiply by 7.48 gallons/cu ft to get gallons.

You'll need to 'fudge it a bit for rounding in the deep end especially, and also the stairs, but this shoudl get you within 5% of real value